#include <stdio.h>
#include <math.h>

int main(int argc, char *argv[]) {

    double num;
    int res;
    scanf("%lf", &num);
    if (num<1000)
    {
        res = sqrt(num);
        printf("%d", res);
    }else{
        printf("invalid data!");
    }
    

    return 0;
}